import java.util.Scanner;

/**
 * 计算字符串中含有的不同字符的个数。字符在ACSII码范围内(0~127)。不在范围内的不作统计。
 * Created by JiaJia on 2019/6/19 0019.
 */
public class HuaWei010 {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        while (scanner.hasNext()){
            String str=scanner.nextLine();
            System.out.println(countChar(str));
        }
        scanner.close();
    }
    private static int countChar(String str){
        int[] arr=new int[128];
        for (int i = 0; i <str.length() ; i++) {
            if (str.charAt(i)>=0 && str.charAt(i)<=127){
                arr[str.charAt(i)]++;
            }
        }
        int count=0;
        for (int i:arr) {
            if (i!=0)
                count++;
        }
        return count;
    }
}